Trends in the prevalence and incidence of Crohn's disease in Japan and the United States

Purpose This study is to describe patient demographic characteristics and estimate annual prevalence and incidence rates of Crohn's disease (CD) in Japan and the United States (US). Methods Two large employment-based healthcare claims databases (Japan Medical Data Center [JMDC] in Japan and Merative MarketScan [Merative] in the US) were used to identify patients with CD from 2010 to 2019. Cases were confirmed using an algorithm based on diagnostic with/without treatment codes. The Merative population was used for sex and age standardization of annual prevalence and incidence rates estimated from the JMDC. Results Patients with CD were generally younger in Japan than in the US at diagnosis (mean 33.6 vs. 39.4 years) and 71.5% were male versus 45.1% in the US. Annual prevalence per 100,000 population increased substantially in both countries, from 34.2 in 2010 to 54.5 in 2019 in Japan (standardized) and 163.3 to 224.2 in the US. Prevalence rates increased in both males and females in all age groups between 6 and < 65 years. Annual incidence rate per 100,000 person-years was almost fourfold higher in the US than Japan (21.0 vs. 5.5 [standardized] in 2019) but remained stable in both countries over time in both sexes and in all age groups. Conclusion The epidemiology of CD differs between Japan and the US. Research to understand the basis of these differences could help to identify at-risk groups in each country, and guide implementation of preventive measures.